The main difference of producing primary, secondary and tertiary alcohol are-
i. For producing primary alcohol we need Formaldehyde that react with Methylmagnesium chloride(CH3MgCl).
ii. For producing secondary alcohol we need Acetaldehyde that react with Methylmagnesium chloride(CH3MgCl).
iii. For producing tertiary alcohol we need Acetone that react with Methylmagnesium chloride(CH3MgCl).